Would you need to show a passport at the border of an independent Scotland?

The notion of passport checks at the Scottish-English border seems almost ludicrous. A deal to keep an independent Scotland within the common travel area – as Ireland is – looks to be the most straightforward solution.

But immigration could be a real obstacle to such a political settlement. Scotland is likely to take a more relaxed tack on immigration, which a Westminster government could object to, meaning it is not a foregone conclusion that the border would remain passport free.

• Read more on how the England-Scotland border might operate in the event of independence